WITH many March lambing ewes now housed, farm-ers are looking the most effective way to feed their ewes this winter.
Pre-lambing feeding will have a major influence on lamb birth weight, lamb vigour, lamb survival, colostrum produced by the ewe and ewe condition. These factors all impact the profitability of the sheep enterprise.
Beef and Sheep Adviser Brian Hanthorn from the College of Agriculture Food and Rural Enter-prise (CAFRE), stated: “70-75 per cent of foetal growth takes place in the last 6-7 weeks of pregnancy and the energy demand on the ewe rises dramatically.”
The growing lambs reduce the space available for the ewe’s rumen, subsequently reducing appetite by
up to 30 per cent. Concentrated energy is required at this stage in the form of concentrates or meal. Lack of adequate feeding in late pregnancy can result in higher levels of twin lamb disease, ewes in poor body condition at lambing, poor lamb viability, low lamb birth weights and survival as well as very poor colostrum quality and quantity.
Colostrum is a vital component in lamb survival and Mr Hanthorn added: “If a lot of powdered colostrum has to be used to supplement lambs at birth this can be an indication that there are shortfalls in the feeding plan.
“Studies have shown that ewes receiving adequate nutrition pro-duced almost twice the colostrum during the 18 hours after lambing compared to underfed ewes. It is essential to get the feeding right.”
Maximising use of top quality silage is where any feeding plan should begin. The first step is silage analysis to get an indication of its feeding value. The best silage available should be fed to sheep, preferably first cut with a metabolisable energy (ME) of over 11 MJ/kg DM. It should be well fermented and have no mould or soil contamination. Mr Hanthorn stated: “Precision chop silage is preferred over round bales as the shorter chop length results in higher intakes, reducing the quantity of concentrate feeding required.”
However, many sheep farmers still feed round bales to sheep and chop length is getting shorter due to more blades in the chopping mechanism of round balers.
Significant savings on concentrates can be made by feeding excellent quality silage compared to poor quality silage (see Table 1).
Silage should be offered on an ab- lib basis and a minimum of 15cm of feed space per ewe is needed to ensure all ewes have good access to the forage.
It is also important to balance the protein level in the meal with the protein available from the silage. Mr Hanthorn commented: “Concentrate feeds are not all the same and sheep farmers should look carefully at the list of ingredients on the feed label.” Ingredients are listed in descending order of inclusion rate.
Mr Hanthorn added: “Ewe con-centrates can vary from 16-21 per cent protein and the type of protein is really important, especially in prolific flocks.”
Soya bean meal is a good bypass protein source and should be the top protein source on the feed label, despite it being expensive this year. Good quality proteins are essential in the last 2-3 weeks of pregnancy and in early lactation to ensure the right quality and quantity of colostrum and milk is available to lambs.
Rapeseed meal may also feature on feed labels this year, however
the digestibility of protein is not as good as soya and it is also lower in energy.
Maize distillers are used in some ewe rations and are high in protein and energy, however it should be used at lower inclusion rates to avoid copper toxicity.
Energy sources in a good ewe concentrate should be made up of cereals, mainly maize, barley or wheat, and these should be positioned well up the list on the feed label. Sugar beet pulp is a useful energy source coupled with high fibre levels.
Soya hulls are present in most ewe rations mainly as a fibre provider, however they should not form a high percentage of the diet.
Ingredients such as oatfeed and sunflower, which are lower in energy, would not be expected to feature in high quality ewe rations.
Protected fats are becoming more common in some of the better quality ewe rations. They significantly improve the energy of the ration, which is useful where high lambing percentages are expected. They will not interfere with rumen function and are broken down in the ewe’s abomasum.
Feeding concentrates twice daily is recommended over once daily to reduce the chance of acidosis and put less pressure on the ewe’s rumen. This is especially important when feed levels are above 0.5kg per head per day
Feed space per ewe should be 45cm and this is critical so that every ewe can eat comfortably.
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